comments of the week: ideal stop spacing is 400m?

My experiences in Leeds and Baltimore confirm the validity of a 400m standard for stop spacing. Rarely do you get to experiment with reducing or increasing stop spacing, but we can look at the sum of the experience of the two cities.

In Leeds, there have been a number of routes, normally small single-deck buses running every 30-60 minutes, that have stopped frequently and taken local roads to penetrate various neighbourhoods better than the frequent, relatively fast buses on the main arterials.

These have pretty much all disappeared with time, because people always proved willing to walk about 400m to the main arterials, which is about the furthest you're ever expected to. My experience of occasionally catching one of the slower local routes is that I would be the only passenger.

So, this demonstrates that people really are willing to walk to speed and frequency.

Meanwhile, in Baltimore, buses do stick to the main arterials. But they stop at every corner, just like the streetcars before them, which in Baltimore is about every 120 metres. And hell, are they slow - from Catonsville, MD to downtown Baltimore, I frequently spent 50 minutes to an hour to travel 8 miles that can be driven in about 20 minutes.

What's more, it's an uncomfortable ride, because the bus pulls violently to the corner at every corner, to keep the hell out of the way of traffic. And that's actually the problem with the frequent stops in Baltimore - while boarding time is a bit more complicated (though there's a fixed element to people getting up and making their way out of the bus, and people waiting for the driver's nod to start boarding), you can basically multiply the time spent waiting to pull out back into traffic by the number of stops.

So what you have is a slow service, and by that virtue, a less frequent service, because one bus can make fewer trips. So, if people will walk to speed and frequency where delivered by different routes, then we can assume that people will also walk to speed and frequency on existing routes when that's achieved by means of widely spaced stops.

In thinking about this sexless but profoundly consequential issue, you may want to refer back to this post, which clarifies the concepts of coverage gaps and duplicate coverage areas. (See that post for more explanation of this figure.)

Balancing these two considerations is the essence of the stop spacing task. Closer stop spacing means smaller coverage gaps but more wasteful duplication of coverage area. So a lot depends on the local land use. If there's more stuff along the transit corridor than in the coverage gaps, that argues for pushing stops wider.

The European HiTrans guides suggest 600m for stop spacing in busy areas where demand is high and local access is the intent. In general, Europeans and Australians are willing to go wider than North Americans in a similar setting.

So why on earth does any transit agency that aims to compete with cars put stops as close as 120m?? Well, these things creep up on you. If ridership is so low that you won't be stopping at every stop anyway, close spacing doesn't present much of a problem. But once ridership reaches the level where you're stopping at every stop, close spacing requires you to stop more, and thus run more slowly, to serve the same number of people.

On the tradition of very-close North American spacing, John offered an interesting speculation:

"But right now, a lot of transit (in North America especially) seems designed to compete with walking, rather than with the car. Do we have the balance right?"

I think the balance is off, and I think it's largely a legacy of the streetcar era, when transit only needed to be faster than walking to draw a huge mode share. In that situation, minimizing walking distance made sense. Then the competition changed when cars came along and average trip distances increased. The streetcars were removed, but nobody ever bothered to change the stop spacing. Now transit isn't time-competitive, and in most cities it serves only the transit-dependent and niche markets like express routes to the CBD.

Is very close stop spacing on North American bus systems really so old that it predates the car, and therefore reflects the competitive situation between transit and its alternatives as it was around 1910? That would be some sort of record for failure to adapt: a habit that has survived for an entire century after its obsolescence.

Obviously, too, many North American services aren't trying to compete with the car; they're social services intended only for the transit dependent, and in those cases travel time is presumed to travel less. But be careful about taking that attitude too far.

Comments

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In a few cases, there's a legitimate argument for short stop spacing - for example, if there are natural destinations occurring every 200 meters. This is about the furthest I'd be willing to take the elevator analogy.

It's usually more important to hit major destinations than to maintain a consistent stop spacing. In Manhattan, crosstown buses should and do stop almost every avenue, leading to stop spacing of about 280 meters Uptown, while north-south buses should make about the same stops as the most local subways (and in reality stop much more often), leading to stop spacing of about 500 meters. Different cities have different street network geometries: just as some lend themselves to grids better than others, so do some lend themselves to a certain stop spacing.

@Alon To again take Baltimore, with a grid that's slightly irregular but averages at about 120 metres between streets, you clearly don't want 400 metres - you want 240 or 360, depending upon how bold you're being.

In Leeds, meanwhile, while stops are spaced quite rigidly at 400 metres apart, there's a second stop making up 200m spacing past the university, because the main buildings warrant their own stop.

And, of course, if there's a major arterial crossing, possibly with another service you might want to transfer to, you want a stop there even if it's not far past the previous stop.

My general rule of thumb is that you should look at a range between 250 and 400 metres, picking out which are the most important cross streets with the most significant access to places on either side of the road.

The first stop consolidation project that I know of was in Cleveland around 1911 or 1912. I seem to have lost my report on this, but you can read about it in the 1913 Electric Railway Journal, page 141 (it has been digitized by Google). Readings of the time indicate that transit companies viewed walking as their main competitor. There is good readings on stop consolidation over the following two decades. It seems to me that as transit became a publicly owned utility, stop consolidation was abandoned since one of the arguments for public ownership of transit was to preserve the current system of routes and schedules. (other sources: 1926 Westinghouse report to City of Seattle recommended to "analyze stop requirements to inaugarate a system of selective (skip) stops thereby improving schedule speeds and reducing operating costs" and the seminal 1921 work entitled "Analysis of the Electric Railway Problem" provides a wealth of information on historical recommendations that mirror the HT blog)

An additional factor in U.S. stop spacing - the transit company may not always have the ability to control the spacing of the stops. In New Jersey, the municipality must designate the stop locations. If the road is a county road, the county must concur. If the road is a state highway, the state D.O.T. must concur.

While many municipalities work with the transit companies to place stops at reasonable distances, some municipalities are not at all cooperative.

Sorry, but are you seriously defending the New York practice of stopping at every avenue? It's madness. We have the slowest buses in the world and this is the biggest reason they are so slow.

By contrast, look at the spacing of crosstown subway routes. It's kind of annoying to transfer from the 1 to the L, but walking over one avenue is better than having 5 or 6 stops slowing down the L in Manhattan.

I'm amazed reading the comments that no-one has approached this problem mathematically. If you put in values for walking speed, transit speed (adjusting for greater speed with longer stops), and journey length, then what you find is quite straight-forward and intuitively obvious: optimum stop distance is a function of journey length.

If you are travelling 1-5km, then stops need to be 400-600m apart or you spend most of your time walking. If 10-20km, then the optimum stop distance is 1-2km, or you spend too much time on transit. If you are in a elevator going 50m, then optimal stop distance is almost certainly every floor. Conversely, taller buildings have express elevators to deal with that very issue.

If you are designing transit to go both long distances and short distances, then you have a problem. Either you need to serve one market (or more) in a sub-optimal way; or you actually need two transit options: one that runs express between major stops (which can then be 3-4km apart), and one that stops more frequently to pick up walkers.

There's the interesting paradox that as ridership goes up, you should decrease the number of stops.

Say you have a suburban commuter route that gets 10 riders per bus.

It could have a bus stop every 50m, thus providing what is essentially door-to-door service to the commuters. And because it will make only 10 stops (1 per passenger) it doesnt matter that the route has 82 stops, the trip is still as fast as traffic will allow.

Meanwhile, a bus with 250 riders (people getting on and off the 40-person bus as it makes its way down the route) needs stops spaced further apart. If the 82 stops are kept, the bus might just stop at every single one to accommodate the 250 riders. But we cant have that! The agency must set aside 20 stops, and "bundle" the riders at those.

So the riders give up convenience but gain speed.

It would be interesting for a transit agency to offer stops served during peak hours and off peak hours. For example, to stop at pre-determined stops during rush hours, but allow riders to get on or off at ANY point during off peak hours. That way, you get the best of both.

Im sure all of you have had the experience where you're on an empty bus, and wish you could tell the driver to just drop you off at your house, instead of 3 blocks away, but can't, because the practice isn't allowed. And on the opposite side, you've slowly died as your bus stops every 20 feet during busy hours.

When Im in Boston, I love taking the 77 home after 10pm. It's like a private express bus. 10 people get on at the starting point, and the bus makes 6 stops to drop them off (nobody gets on further down the route). At 6pm? The route takes exactly twice as much, because it services every single stop as people want to get on and off and on and off again.

I would agree in the strongest possible terms that European system don't try to compete with walking in a way that American ones most definitely do. I'm not entirely convinced that this comes down to a refusal to adapt from the market situation pre car, but honestly it wouldn't surprise me given the state of this business in North America.

I suspect that this is really more of a philosophical issue. There seems to be a very strong belief that North Americans are averse to walking, while the European transit systems seem to expect that passengers will prefer to walk if the distance is practical than wait and pay for the transit service. How true the assumptions are is open to question, as are their origins, but I think it is pretty clear which results in a more efficient transit system and more liveable city.

@Tsuyoshi: under the current practice of one-way pairs, yes, I'm defending crosstown bus stop spacing. Those buses are slow not because they make frequent stops, but because there's traffic congestion and the the stoplights are engineered to optimize north-south traffic. I'd welcome limited-stop buses on high-ridership corridors, e.g. 14th, 86th, 125th, but the rest aren't important or frequent enough to merit both local and limited buses.

Under better operating practices, which include restoring two-way service on the avenues, I might change my mind. It would have to depend on traffic patterns, but presumably some buses could stop 5-6 times in 3 km instead of 10 times. It depends on whether some avenues would become clearly busier than others; Madison would almost certainly be much busier than Fifth, but I have no idea about the other four one-way pairs.

Where a route crosses service on a one-way couplet, rigid adherence to longer stop spacing standards can make transfers much more annoying. When riders are forced to wait and ride through possibly two traffic lights, then walk back across the same two streets, plus an intervening block, the transfer movement is discouraged.

In these situations, I would advocate a near-side stop at the first street, and a far-side stop at the second street. I believe that this is not done more often because transit management does not consistently value transfers (or connections, as Jarrett prefers).

It is interesting to note that in the few instances where trams are being modernised or re-introduced in the UK using high capacity vehicles, stop spacing is being increased, e.g. the modernised coastal tramway in Blackpool and the Ashton New Road service in Manchester, both due to be inaugurated in 2012. The latter line will have come full circle - it was operated by trams until 1938, then trolleybuses (1938-1966) and is currently a bus route!

No way 400m. Unless your block lengths are very long, 400m is almost every three blocks. You've got to realize it's not so much distance as much as the number of streets one has to cross, which consumes time and generates stress. Transit has got to serve the elderly and disabled. If they quit riding the bus, they're going to go to paratransit--and that costs 4 to 10 times as much to operate. There can be a diverse mix of services on heavily traveled corridors (i.e. limited bus and rapid transit), but some buses need to stop at least every other block. And more often in high density areas or where there are transfers.

I like the comment from above, it doesn't save time for many people, let alone those who are required to be served by the State.

No matter what you do, the local bus is still going to be slow (assuming you don't drive the all the riders away). The nuisance of walking longer to your stop is not made up for in the 20% increase in operating speed. Having stops far apart make the bus more difficult to catch in that one is more likely to between stops when the bus comes by!

Traveling from Catonsville to downtown Baltimore is slow because Frederick Ave is slow more than anything.

In New York, 400 meters is 5 blocks. But it's not a huge deal - yes, the elderly can't walk very far, but 400-500 is not a dealbreaker in Switzerland or Germany or the Netherlands or France, and doesn't increase operating costs. On the contrary: faster buses require fewer salaries to pay for a given level of service, and induce higher ridership.

I would like to see a system with nice wide stop spacing (every 1/2 mile or so), but with the caveat that when the bus is stopped at a traffic light anyway between stops, the doors open and anyone who wants to get off the bus can get off.

This increases convenience for passengers, plus improves speed as well - if people already got off at the stoplight just before the bus stop, you can blow by the bus stop without having to stop again a second time.

Similarly, if the bus stop is before the intersection and the bus is stopped 50 feet before the bus stop in a line of cars, just open the doors and let people off, rather than wait for light to change, everyone in front to move, stop again at the stop to let people off, start moving again, wait for the light a second time (because it's now turned red again), etc.

I spent some time playing with Google Maps last night, and while I didn't look at EVERY European transit system, I found most buses stopped about every 300m, more or less while metros stopped about every 800m. While these distances may seem small, it is worth noting that many of these cities are much smaller in area and more compact than those in North American ones.

so here in Berkeley-Oakland we have a major bus route with daylight only M-F Rapid service, not full BRT but much faster than the local. In the evenings, the local is time competitive to the Rapid because many stops are skipped account much lighter ridership thus fewer stops whether "local" or "rapid". This demonstrates how both markets can be served by tailored services whereas neither alone would be as useful.

Baltimore actually tried to rationalize its bus system a few years ago - not by reducing stop spacing, but by consolidating bus lines that travel in parallel a block or two apart. A *lot* of older people came out to the public meetings and said this would be a hardship for them -- enough that it scuppered the revamp. Like it or not, this is a constituency that will be important to the transit decision-making calculus if you have any sort of public meetings.

Im sure all of you have had the experience where you're on an empty bus, and wish you could tell the driver to just drop you off at your house, instead of 3 blocks away, but can't, because the practice isn't allowed.

In Portland this practice actually is allowed at certain hours. Though it's never actually helped me.

I'm in San Francisco right now and considering another reason to stop more often: if you're going right up a steep hill, it's a bit more of a hardship for people to walk the extra block or two. Though it's not obvious to me that the stop locations are actually sensitive to this.

Notwithstanding that, I would prefer to see Muni ditch the majority of their every-block stops; it's just madness, especially in highly congested corridors and with far-side stops where the bus often stops at the light and then stops at the stop as well.